You need to determine which
application will install when a user attempts to access a
file. This is done by selecting the specific file
extensions on the File Extensions tab of the Software
Installation Properties page.

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The application that is the
highest in the Application Precedence list box is the
application installed when a document with the selected file
name extension is accessed before the application has been
installed on a given system or to a specific user. For example, if you
attempt to access FILENAME.xls and both Excel and Lotus
1-2-3 are listed in the box and neither is installed, Excel
is the program that will be installed.

File extension associations and
which applications are installed upon file access are
managed individually in each Group Policy Object.

Application Categories can be
created to make it easier for users to locate the
appropriate application from within Add/Remove Programs in
Control Panel. Application Categories that Administrators
define are set on a domain-wide basis.

This is done on the Categories tab
of the Software Installation Properties page by clicking on
the Add button at the bottom of the property sheet and
then entering a name for the new category in the "Enter New
Category" dialog box.